/*
 * Copyright (c) 2012 Stefano Sabatini
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * audio to video multimedia filter
 */

#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "avfilter.h"
#include "formats.h"
#include "audio.h"
#include "video.h"
#include "internal.h"

enum ShowWavesMode {
    MODE_POINT,
    MODE_LINE,
    MODE_P2P,
    MODE_CENTERED_LINE,
    MODE_NB,
};

typedef struct {
    const AVClass *class;
    int w, h;
    AVRational rate;
    int buf_idx;
    int16_t *buf_idy;    /* y coordinate of previous sample for each channel */
    AVFrame *outpicref;
    int req_fullfilled;
    int n;
    int sample_count_mod;
    enum ShowWavesMode mode;
    int split_channels;
    void (*draw_sample)(uint8_t *buf, int height, int linesize,
                        int16_t sample, int16_t *prev_y, int intensity);
} ShowWavesContext;

#define OFFSET(x) offsetof(ShowWavesContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

static const AVOption showwaves_options[] = {
    { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "600x240"}, 0, 0, FLAGS },
    { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "600x240"}, 0, 0, FLAGS },
    { "mode", "select display mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=MODE_POINT}, 0, MODE_NB-1, FLAGS, "mode"},
        { "point", "draw a point for each sample",         0, AV_OPT_TYPE_CONST, {.i64=MODE_POINT},         .flags=FLAGS, .unit="mode"},
        { "line",  "draw a line for each sample",          0, AV_OPT_TYPE_CONST, {.i64=MODE_LINE},          .flags=FLAGS, .unit="mode"},
        { "p2p",   "draw a line between samples",          0, AV_OPT_TYPE_CONST, {.i64=MODE_P2P},           .flags=FLAGS, .unit="mode"},
        { "cline", "draw a centered line for each sample", 0, AV_OPT_TYPE_CONST, {.i64=MODE_CENTERED_LINE}, .flags=FLAGS, .unit="mode"},
    { "n",    "set how many samples to show in the same point", OFFSET(n), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },
    { "rate", "set video rate", OFFSET(rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
    { "r",    "set video rate", OFFSET(rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
    { "split_channels", "draw channels separately", OFFSET(split_channels), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, FLAGS },
    { NULL }
};

AVFILTER_DEFINE_CLASS(showwaves);

static av_cold void uninit(AVFilterContext *ctx)
{
    ShowWavesContext *showwaves = ctx->priv;

    av_frame_free(&showwaves->outpicref);
    av_freep(&showwaves->buf_idy);
}

static int query_formats(AVFilterContext *ctx)
{
    AVFilterFormats *formats = NULL;
    AVFilterChannelLayouts *layouts = NULL;
    AVFilterLink *inlink = ctx->inputs[0];
    AVFilterLink *outlink = ctx->outputs[0];
    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE };
    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };

    /* set input audio formats */
    formats = ff_make_format_list(sample_fmts);
    if (!formats)
        return AVERROR(ENOMEM);
    ff_formats_ref(formats, &inlink->out_formats);

    layouts = ff_all_channel_layouts();
    if (!layouts)
        return AVERROR(ENOMEM);
    ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);

    formats = ff_all_samplerates();
    if (!formats)
        return AVERROR(ENOMEM);
    ff_formats_ref(formats, &inlink->out_samplerates);

    /* set output video format */
    formats = ff_make_format_list(pix_fmts);
    if (!formats)
        return AVERROR(ENOMEM);
    ff_formats_ref(formats, &outlink->in_formats);

    return 0;
}

static int config_output(AVFilterLink *outlink)
{
    AVFilterContext *ctx = outlink->src;
    AVFilterLink *inlink = ctx->inputs[0];
    ShowWavesContext *showwaves = ctx->priv;
    int nb_channels = inlink->channels;

    if (!showwaves->n)
        showwaves->n = FFMAX(1, ((double)inlink->sample_rate / (showwaves->w * av_q2d(showwaves->rate))) + 0.5);

    showwaves->buf_idx = 0;
    if (!(showwaves->buf_idy = av_mallocz_array(nb_channels, sizeof(*showwaves->buf_idy)))) {
        av_log(ctx, AV_LOG_ERROR, "Could not allocate showwaves buffer\n");
        return AVERROR(ENOMEM);
    }
    outlink->w = showwaves->w;
    outlink->h = showwaves->h;
    outlink->sample_aspect_ratio = (AVRational){1,1};

    outlink->frame_rate = av_div_q((AVRational){inlink->sample_rate,showwaves->n},
                                   (AVRational){showwaves->w,1});

    av_log(ctx, AV_LOG_VERBOSE, "s:%dx%d r:%f n:%d\n",
           showwaves->w, showwaves->h, av_q2d(outlink->frame_rate), showwaves->n);
    return 0;
}

inline static int push_frame(AVFilterLink *outlink)
{
    AVFilterContext *ctx = outlink->src;
    AVFilterLink *inlink = ctx->inputs[0];
    ShowWavesContext *showwaves = outlink->src->priv;
    int nb_channels = inlink->channels;
    int ret, i;

    if ((ret = ff_filter_frame(outlink, showwaves->outpicref)) >= 0)
        showwaves->req_fullfilled = 1;
    showwaves->outpicref = NULL;
    showwaves->buf_idx = 0;
    for (i = 0; i < nb_channels; i++)
        showwaves->buf_idy[i] = 0;
    return ret;
}

static int request_frame(AVFilterLink *outlink)
{
    ShowWavesContext *showwaves = outlink->src->priv;
    AVFilterLink *inlink = outlink->src->inputs[0];
    int ret;

    showwaves->req_fullfilled = 0;
    do {
        ret = ff_request_frame(inlink);
    } while (!showwaves->req_fullfilled && ret >= 0);

    if (ret == AVERROR_EOF && showwaves->outpicref)
        push_frame(outlink);
    return ret;
}

static void draw_sample_point(uint8_t *buf, int height, int linesize,
                              int16_t sample, int16_t *prev_y, int intensity)
{
    const int h = height/2 - av_rescale(sample, height/2, INT16_MAX);
    if (h >= 0 && h < height)
        buf[h * linesize] += intensity;
}

static void draw_sample_line(uint8_t *buf, int height, int linesize,
                             int16_t sample, int16_t *prev_y, int intensity)
{
    int k;
    const int h = height/2 - av_rescale(sample, height/2, INT16_MAX);
    int start   = height/2;
    int end     = av_clip(h, 0, height-1);
    if (start > end)
        FFSWAP(int16_t, start, end);
    for (k = start; k < end; k++)
        buf[k * linesize] += intensity;
}

static void draw_sample_p2p(uint8_t *buf, int height, int linesize,
                            int16_t sample, int16_t *prev_y, int intensity)
{
    int k;
    const int h = height/2 - av_rescale(sample, height/2, INT16_MAX);
    if (h >= 0 && h < height) {
        buf[h * linesize] += intensity;
        if (*prev_y && h != *prev_y) {
            int start = *prev_y;
            int end = av_clip(h, 0, height-1);
            if (start > end)
                FFSWAP(int16_t, start, end);
            for (k = start + 1; k < end; k++)
                buf[k * linesize] += intensity;
        }
    }
    *prev_y = h;
}

static void draw_sample_cline(uint8_t *buf, int height, int linesize,
                              int16_t sample, int16_t *prev_y, int intensity)
{
    int k;
    const int h     = av_rescale(abs(sample), height, INT16_MAX);
    const int start = (height - h) / 2;
    const int end   = start + h;
    for (k = start; k < end; k++)
        buf[k * linesize] += intensity;
}

static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
{
    AVFilterContext *ctx = inlink->dst;
    AVFilterLink *outlink = ctx->outputs[0];
    ShowWavesContext *showwaves = ctx->priv;
    const int nb_samples = insamples->nb_samples;
    AVFrame *outpicref = showwaves->outpicref;
    int linesize = outpicref ? outpicref->linesize[0] : 0;
    int16_t *p = (int16_t *)insamples->data[0];
    int nb_channels = inlink->channels;
    int i, j, ret = 0;
    const int n = showwaves->n;
    const int x = 255 / ((showwaves->split_channels ? 1 : nb_channels) * n); /* multiplication factor, pre-computed to avoid in-loop divisions */
    const int ch_height = showwaves->split_channels ? outlink->h / nb_channels : outlink->h;

    /* draw data in the buffer */
    for (i = 0; i < nb_samples; i++) {
        if (!showwaves->outpicref) {
            showwaves->outpicref = outpicref =
                ff_get_video_buffer(outlink, outlink->w, outlink->h);
            if (!outpicref)
                return AVERROR(ENOMEM);
            outpicref->width  = outlink->w;
            outpicref->height = outlink->h;
            outpicref->pts = insamples->pts +
                             av_rescale_q((p - (int16_t *)insamples->data[0]) / nb_channels,
                                          (AVRational){ 1, inlink->sample_rate },
                                          outlink->time_base);
            linesize = outpicref->linesize[0];
            for (j = 0; j < outlink->h; j++)
                memset(outpicref->data[0] + j * linesize, 0, outlink->w);
        }
        for (j = 0; j < nb_channels; j++) {
            uint8_t *buf = outpicref->data[0] + showwaves->buf_idx;
            if (showwaves->split_channels)
                buf += j*ch_height*linesize;
            showwaves->draw_sample(buf, ch_height, linesize, *p++,
                                   &showwaves->buf_idy[j], x);
        }

        showwaves->sample_count_mod++;
        if (showwaves->sample_count_mod == n) {
            showwaves->sample_count_mod = 0;
            showwaves->buf_idx++;
        }
        if (showwaves->buf_idx == showwaves->w)
            if ((ret = push_frame(outlink)) < 0)
                break;
        outpicref = showwaves->outpicref;
    }

    av_frame_free(&insamples);
    return ret;
}

static av_cold int init(AVFilterContext *ctx)
{
    ShowWavesContext *showwaves = ctx->priv;

    switch (showwaves->mode) {
    case MODE_POINT:         showwaves->draw_sample = draw_sample_point; break;
    case MODE_LINE:          showwaves->draw_sample = draw_sample_line;  break;
    case MODE_P2P:           showwaves->draw_sample = draw_sample_p2p;   break;
    case MODE_CENTERED_LINE: showwaves->draw_sample = draw_sample_cline; break;
    default:
        return AVERROR_BUG;
    }
    return 0;
}

static const AVFilterPad showwaves_inputs[] = {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_AUDIO,
        .filter_frame = filter_frame,
    },
    { NULL }
};

static const AVFilterPad showwaves_outputs[] = {
    {
        .name          = "default",
        .type          = AVMEDIA_TYPE_VIDEO,
        .config_props  = config_output,
        .request_frame = request_frame,
    },
    { NULL }
};

AVFilter ff_avf_showwaves = {
    .name          = "showwaves",
    .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a video output."),
    .init          = init,
    .uninit        = uninit,
    .query_formats = query_formats,
    .priv_size     = sizeof(ShowWavesContext),
    .inputs        = showwaves_inputs,
    .outputs       = showwaves_outputs,
    .priv_class    = &showwaves_class,
};
